Lead identification system

ABSTRACT

A lead identification system for tracking a plurality of neurostimulation leads during implantation in a patient, and a method of using the same. The lead identification system includes a plurality of lead indicators each adapted to attach to one of a plurality of epidural needles to identify the leads. At least one clip adapted to releasably attach to proximal ends of the leads is provided with corresponding lead indicators. The trial cable for conducting trial stimulation includes connectors with corresponding lead indicators. A plurality of lead indicator stylets are provided for insertion into lumens at the proximal ends of the leads. The pulse generator also has connectors with corresponding lead indicators. The various lead indicators permit a surgeon to track a particular lead to the corresponding connectors on the pulse generator.

FIELD

The present disclosure relates to a lead identification system formultiple neurostimulation leads during implantation within a livingbody.

BACKGROUND

Implantable neurostimulation systems have proven therapeutic in a widevariety of diseases and disorders. These implantable neurostimulationsystems typically include one or more stimulation leads implanted at thedesired stimulation site and an implantable neurostimulator, such as animplantable pulse generator (IPG), implanted remotely from thestimulation site, but coupled either directly to the stimulation leadsor indirectly to the stimulation leads via one or more lead extensionsin cases where the length of the stimulation leads is insufficient toreach the IPG.

In the context of an SCS procedure, one or more stimulation leads areintroduced through the patient's back into the epidural space underfluoroscopy, such that the electrodes carried by the leads are arrangedin a desired pattern and spacing to create an electrode array. Afterproper placement of the stimulation leads at the target area of thespinal cord, the leads are anchored in place at an exit site to preventmovement of the stimulation leads. Whether lead extensions are used ornot, the proximal ends of the stimulation leads exiting the spinalcolumn are passed through a tunnel subcutaneously formed along the torsoof the patient to a subcutaneous pocket (typically made in the patient'sabdominal or buttock area) where a neurostimulator is implanted.

The stimulation leads are then connected directly to the neurostimulatorby inserting the proximal ends of the stimulation leads within one ormore connector ports of the IPG or connected to lead extensions, whichare then inserted into the connector ports of the IPG. The IPG can thenbe operated to generate electrical pulses that are delivered, throughthe electrodes, to the targeted tissue, and in particular, the dorsalcolumn and dorsal root fibers within the spinal cord.

Oftentimes, multiple lead bodies may extend from the spinal region ofthe patient. For example, multiple percutaneous leads may be implantedwithin the patient adjacent the spinal cord, or in the case of paddleleads, multiple lead tails may extend from the paddle, with each leadtail being coupled to specific electrodes on the paddle. Because theprogramming of the IPG will depend upon the physical locations of theelectrodes relative to the patient's spinal cord, the proximal ends ofthe lead bodies are labeled before passing them through the tunnelingstraw, so that the surgeon can keep track of which set of electrodes isconnected to which connector port on the implanted IPG (which mayinclude up to four ports in the near future), or if multiple IPGs are tobe implanted, which set of electrodes is connected to which IPG.

One technique used by surgeons to identify the lead bodies is to tiesutures around the proximal ends of the lead bodies prior to introducingthem through the tunneling straw; for example, one suture around a firstlead body, two sutures around a second lead body, three sutures around athird lead body, etc. Once the proximal ends of the lead bodies exit thetunneling straw, the surgeon can then identify each lead body (and thusthe corresponding electrodes) by the number of sutures tied to therespective lead body, thereby allowing the lead body to be connected tothe correct port on the IPG.

While this technique can be successfully employed to identify leadbodies, it considerably extends the length of the surgery time, which isundesirable. In some cases, the identification features, such asdifferent colors or markings, can be incorporated into the proximal endsof the lead bodies, such that the lead bodies can be identified as theyexit the tunneling straw. If the lead bodies are inserted into theincorrect connector ports, intra-operative testing of the lead placementmay be compromised. Additional surgical time may be wasted to identifyand correct the connection problem. If the errors remain unidentified,the patient may leave the operating room with the lead bodiesincorrectly connected. During post-operative fitting, additional timemay then be lost identifying and compensating for lead bodies that arenot in the proper connector ports. This ultimately can result insub-optimal therapy.

BRIEF SUMMARY

The present disclosure relates to a lead identification system formultiple neurostimulation leads that permits the surgeon to trackelectrodes on a particular lead to the correct connectors on theimplantable pulse generator.

The present lead identification system provides corresponding leadindicators that permit the surgeon to track the electrodes of aparticular therapy delivery element to the correct connectors on animplantable pulse generator. The lead indicators are preferablyreleasably attachable to the components of the neurostimulation systemand can be shifted or reconfigured by the surgeon during the procedure.Consequently, the components of the neurostimulation system, such as theepidural needles, the leads and lead extensions, lead clips, leadanchors, stylets, internal and external pulse generators, and trialcables can all be generic without any labels or indicia. The use ofremovable lead indicators dramatically reduces the inventory ofcomponents for the neurostimulation system.

One embodiment is directed to a method of implanting a plurality oftrial neurostimulation leads in a patient. An epidural needle isinserted into the patient for each trial lead. A trial lead is insertedthrough each epidural needle and positioned in the patient. A removablelead indicator is attached to each epidural needle. Proximal portions ofthe trial leads are attached to a clip with corresponding leadindicators. The proximal ends of the trial leads are electricallycoupled to connectors having corresponding lead indicators on the trialcable. Trial stimulation of the trial leads is conducted to confirm leadplacement. Corresponding lead indicator stylets are inserted in lumensof each of trial lead. The trial leads are disconnected from the trialcable. The epidural needles are removed from the patient by sliding theepidural needles off the trial leads. The incisions around the trialleads are closed. The trial leads are electrically coupled to connectorshaving corresponding lead indicators on an external pulse generator. Theneurostimulation leads are operated during a trial period.

The removable lead indicators can be one or more of color indicators,tactile indicators, alpha-numeric indicators, or a combination thereof.

The present disclosure is also directed to a method of implanting aplurality of permanent neurostimulation leads in a patient. An epiduralneedle is inserted into the patient for each permanent lead. A permanentlead is inserted through each epidural needle and positioned in thepatient. A removable lead indicator is attached to each epidural needle.Proximal portions of the permanent leads are attached to a clip withcorresponding lead indicators. The proximal ends of the permanent leadsare electrically coupled to connectors having corresponding leadindicators on the trial cable. Trial stimulation of the permanent leadsis conducted to confirm lead placement. Corresponding lead indicatorstylets are inserted in lumens of each of permanent lead. The permanentleads are disconnected from the trial cable. The epidural needles areremoved from the patient by sliding the epidural needles off thepermanent leads. The permanent leads are attached to the patient usinganchors having corresponding lead indicators. Proximal ends of thepermanent leads with the corresponding lead indicator stylets are passedthrough one or more lumens to an implantable pulse generator located ata remote implantation site in the patient. The corresponding leadindicator stylets are removed from the lumens of the permanent leads.The proximal ends of the permanent leads are electrically coupled toconnectors having corresponding lead indicators on an implantable pulsegenerator. The incision sites around the permanent leads and theimplantable pulse generator are closed.

The present disclosure is also directed to a method of implanting aplurality of permanent neurostimulation leads with trial lead extensionsin a patient. An epidural needle is inserted into the patient for eachpermanent lead. A permanent lead is inserted through each epiduralneedle and positioned in the patient. A removable lead indicator isattached to each epidural needle. Proximal portions of the permanentleads are attached to a clip with corresponding lead indicators. Theproximal ends of the permanent leads are electrically coupled toconnectors having corresponding lead indicators on a trial cable. Atrial stimulation of the permanent leads is conducted to confirm leadplacement. Corresponding lead indicator stylets are inserted in lumensof each of the permanent leads. The permanent leads are disconnectedfrom the trial cable. The epidural needles are removed from the patientby sliding the epidural needles off the permanent leads. The permanentleads are attached to the patient using anchors having correspondinglead indicators. The removable lead indicator stylets are transferredfrom the permanent leads to lumens at proximal ends of the trial leadextensions. Distal ends of the trial lead extensions are attached toproximal ends of the corresponding permanent leads. Proximal ends of thetrial lead extensions with the corresponding lead indicator stylets arepassed through one or more lumens to a remote implantation site in thepatient. The corresponding lead indicator stylets are removed from thelumens of the trial lead extensions. The trial leads are electricallycoupled to connectors having corresponding lead indicators on anexternal pulse generator. Trial neurostimulation is conducted using theexternal pulse generator.

The present disclosure is also directed to a method of implanting aplurality of permanent neurostimulation leads without lead extensions ina patient. The incision site where trial lead extensions are connectedto the permanent leads is opened. The permanent leads are disconnectedfrom the trial lead extensions. Removable lead indicator stylets areinserted in lumens at proximal ends of the permanent leads. The triallead extensions are removed from the patient. Proximal ends of thepermanent leads with the corresponding lead indicator stylets are passedthrough one or more lumens to a remote implantation site in the patient.The corresponding lead indicator stylets are removed from the lumens ofthe permanent leads. The permanent leads are electrically coupled toconnectors on an implantable pulse generator having corresponding leadindicators. The implantable pulse generator is sealed in theimplantation site in the patient.

The present disclosure is also directed to a method of implanting aplurality of permanent neurostimulation leads with permanent leadextensions in a patient. The incision site where trial lead extensionsare connected to the permanent leads is opened. The permanent leads aredisconnected from the trial lead extensions. Removable lead indicatorstylets are inserted in lumens at proximal ends of the permanent leads.The trial lead extensions are removed from the patient. The removablelead indicator stylets are transferred to lumens at proximal ends of thepermanent lead extensions. Permanent lead extensions are attached to thepermanent leads. The proximal ends of the permanent lead extensions withthe corresponding lead indicator stylets are passed through one or morelumens to a remote implantation site in the patient. The correspondinglead indicator stylets are removed from the lumens of the permanent leadextensions. The permanent lead extensions are electrically coupled toconnectors having corresponding lead indicators on an implantable pulsegenerator. The implantable pulse generator is sealed in the implantationsite in the patient.

The present disclosure is also directed to a lead identification systemfor tracking a plurality of neurostimulation leads during implantationin a patient. The lead identification system includes a plurality ofremovable lead indicators each adapted to attach to one of a pluralityof epidural needles to identify the leads. One embodiment includesrotating lead indicators attach to each of the epidural needles whereina rotational orientation of the rotating lead indicators uniquelyidentify each of the therapy delivery elements. At least one clipadapted to releasably attach to proximal ends of the leads is providedwith corresponding lead indicators. The trial cable for conducting trialstimulation includes connectors with corresponding lead indicators. Aplurality of removable lead indicator stylets are provided for insertioninto lumens at the proximal ends of the leads. A pulse generator isprovided with connectors having corresponding lead indicators. Thevarious removable lead indicators permit a surgeon to track electrodeson a particular lead to the corresponding connectors on the pulsegenerator.

The removable lead indicators can be one or more of color indicators,tactile indicators, alpha-numeric indicators, or a combination thereof.The leads can be trial leads or permanent leads. The pulse generator canbe an external pulse generator for conducting trials or an implantablepulse generator. The lead identification system optionally includes oneor more lead anchors adapted to attach the leads to the patient withcorresponding lead indicators.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a schematic illustration of a therapy delivery system.

FIG. 2 is a schematic illustration of an environment for a therapydelivery system in accordance with an embodiment of the presentdisclosure.

FIG. 3 is an alternate illustration of the environment for animplantable pulse generator with a therapy delivery element inaccordance with an embodiment of the present disclosure.

FIG. 4 is a perspective view of epidural needle adapted to receive aremovable lead indicator in accordance with an embodiment of the presentdisclosure.

FIG. 5 is a schematic illustration of a removable lead indicator on anepidural needle during implantation of a therapy delivery element inaccordance with an embodiment of the present disclosure.

FIG. 6 is a perspective view of a removable lead indicator suitable forattachment to an epidural needles in accordance with an embodiment ofthe present disclosure.

FIG. 7 is a side sectional view of the lead indicator of FIG. 6.

FIG. 8 is a perspective view of an alternate removable lead indicator inaccordance with an embodiment of the present disclosure.

FIG. 9 is a side view of a clip having lead indicators adapted to attachto therapy delivery elements in accordance with an embodiment of thepresent disclosure.

FIG. 10 is a perspective view of a stylet-lead assembly in accordancewith an embodiment of the present disclosure.

FIG. 11 is a perspective view of a trial cable connector with leadindicators in accordance with an embodiment of the present disclosure.

FIG. 12 is a perspective view of a removable lead indicator adapted forinsertion into a lumen of a therapy delivery element in accordance withan embodiment of the present disclosure.

FIG. 13 illustrates a method of using a lead identification system inaccordance with an embodiment of the present disclosure.

FIG. 14 is a flow chart summarizing a method for implanting a pluralityof trial leads using a lead identification system in accordance with anembodiment of the present disclosure.

FIGS. 15A and 15B are flow charts summarizing a method for implanting aplurality of permanent leads using a lead identification system inaccordance with an embodiment of the present disclosure.

FIGS. 16A and 16B are flow charts summarizing a method for implanting aplurality of permanent leads with trial lead extensions using a leadidentification system in accordance with an embodiment of the presentdisclosure.

FIG. 16C is a flow chart summarizing a method of implanting a pluralityof permanent leads, with or without permanent lead extensions, using alead identification system in accordance with an embodiment of thepresent disclosure.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The description that follows relates to a spinal cord stimulation (SCS)system. However, it is to be understood that while the presentdisclosure lends itself well to applications in SCS, the disclosure inits broadest aspects may not be so limited. Rather, the disclosure maybe used with any type of implantable therapy delivery system with one ormore therapy delivery elements. For example, the present disclosure maybe used as part of a pacemaker, a defibrillator, a cochlear stimulator,a retinal stimulator, a stimulator configured to produce coordinatedlimb movement, a cortical stimulator, a deep brain stimulator,peripheral nerve stimulator, microstimulator, or in any other neuralstimulator configured to treat urinary incontinence, sleep apnea,shoulder sublaxation, headache, etc.

In another embodiment, one or more of the therapy delivery elements maybe a fluid delivery conduit, such as a catheter, including an innerlumen that is placed to deliver a fluid, such as pharmaceutical agents,insulin, pain relieving agents, gene therapy agents, or the like from afluid delivery device (e.g., a fluid reservoir and/or pump) to arespective target tissue site in a patient.

In yet another embodiment, one or more of the therapy delivery elementsmay be an electrical lead including one or more sensing electrodes tosense physiological parameters (e.g., blood pressure, temperature,cardiac activity, etc.) at a target tissue site within a patient. In thevarious embodiments contemplated by this disclosure, therapy may includestimulation therapy, sensing or monitoring of one or more physiologicalparameters, fluid delivery, and the like. “Therapy delivery element”includes pacing or defibrillation leads, stimulation leads, sensingleads, fluid delivery conduit, and any combination thereof “Targettissue site” refers generally to the target site for implantation of atherapy delivery element, regardless of the type of therapy.

FIG. 1 illustrates a generalized therapy delivery system 10 that may beused in spinal cord stimulation (SCS), as well as other stimulationapplications. The therapy delivery system 10 generally includes animplantable pulse generator 12 (“IPG”) (“IPG”), an implantable therapydelivery element 14, which carries an array of electrodes 18 (shownexaggerated for purposes of illustration), and an optional implantableextension lead 16. Although only one therapy delivery element 14 isshown, typically two or more therapy delivery elements 14 are used withthe therapy delivery system 10.

The therapy delivery element 14 includes elongated body 40 having aproximal end 36 and a distal end 44. The elongated body 40 typically hasa diameter of between about 0.03 inches to 0.07 inches and a lengthwithin the range of 30 cm to 90 cm for spinal cord stimulationapplications. The elongated body 40 may be composed of a suitableelectrically insulative material, such as, a polymer (e.g., polyurethaneor silicone), and may be co-extruded with the conductors.

In the illustrated embodiment, proximal end 36 of the therapy deliveryelement 14 is electrically coupled to distal end 38 of the extensionlead 16 via a connector 20, typically associated with the extension lead16. Proximal end 42 of the extension lead 16 is electrically coupled tothe implantable pulse generator 12 via connector 22 associated withhousing 28. Alternatively, the proximal end 36 of the therapy deliveryelement 14 can be electrically coupled directly to the connector 22.

In the illustrated embodiment, the implantable pulse generator 12includes electronic subassembly 24 (shown schematically), which includescontrol and pulse generation circuitry (not shown) for deliveringelectrical stimulation energy to the electrodes 18 of the therapydelivery element 14 in a controlled manner, and a power supply, such asbattery 26.

The implantable pulse generator 12 provides a programmable stimulationsignal (e.g., in the form of electrical pulses or substantiallycontinuous-time signals) that is delivered to target stimulation sitesby electrodes 18. In applications with more than one therapy deliveryelement 14, the implantable pulse generator 12 may provide the same or adifferent signal to the electrodes 18.

Alternatively, the implantable pulse generator 12 can take the form ofan implantable receiver-stimulator in which the power source forpowering the implanted receiver, as well as control circuitry to commandthe receiver-stimulator, are contained in an external controllerinductively coupled to the receiver-stimulator via an electromagneticlink. In another embodiment, the implantable pulse generator 12 can takethe form of an external trial stimulator (ETS), which has similar pulsegeneration circuitry as an IPG, but differs in that it is anon-implantable device that is used on a trial basis after the therapydelivery element 14 has been implanted and prior to implantation of theIPG, to test the responsiveness of the stimulation that is to beprovided.

The housing 28 is composed of a biocompatible material, such as forexample titanium, and forms a hermetically sealed compartment containingthe electronic subassembly 24 and battery 26 protected from the bodytissue and fluids. The connector 22 is disposed in a portion of thehousing 28 that is, at least initially, not sealed. The connector 22carries a plurality of contacts that electrically couple with respectiveterminals at proximal ends of the therapy delivery element 14 orextension lead 16. Electrical conductors extend from the connector 22and connect to the electronic subassembly 24.

FIG. 2 illustrates the therapy delivery element 14 implanted in theepidural space 30 of a patient in close proximity to the dura, the outerlayer that surrounds the spinal cord 32, to deliver the intendedtherapeutic effects of spinal cord electrical stimulation. The targetstimulation sites may be anywhere along the spinal cord 32, such as forexample proximate the sacral nerves.

Because of the lack of space near the lead exit point 34 where thetherapy delivery element 14 exits the spinal column, the implantablepulse generator 12 is generally implanted in a surgically-made pocketeither in the abdomen or above the buttocks, such as illustrated in FIG.3. The implantable pulse generator 12 may, of course, also be implantedin other locations of the patient's body. Use of the extension lead 16facilitates locating the implantable pulse generator 12 away from thelead exit point 34. In some embodiments, the extension lead 16 serves asa lead adapter if the proximal end 36 of the therapy delivery element 14is not compatible with the connector 22 of the implantable pulsegenerator 12, since different manufacturers use different connectors atthe ends of their stimulation leads and are not always compatible withthe connector 22.

As illustrated in FIG. 3, the therapy delivery system 10 also mayinclude a clinician programmer 46 and a patient programmer 48. Clinicianprogrammer 46 may be a handheld computing device that permits aclinician to program neurostimulation therapy for patient using inputkeys and a display. For example, using clinician programmer 46, theclinician may specify neurostimulation parameters for use in delivery ofneurostimulation therapy. Clinician programmer 46 supports telemetry(e.g., radio frequency telemetry) with the implantable pulse generator12 to download neurostimulation parameters and, optionally, uploadoperational or physiological data stored by implantable pulse generator12. In this manner, the clinician may periodically interrogate theimplantable pulse generator 12 to evaluate efficacy and, if necessary,modify the stimulation parameters.

Similar to clinician programmer 46, patient programmer 48 may be ahandheld computing device. Patient programmer 48 may also include adisplay and input keys to allow patient to interact with patientprogrammer 48 and the implantable pulse generator 12. The patientprogrammer 48 provides patient with an interface for control ofneurostimulation therapy provided by the implantable pulse generator 12.For example, patient may use patient programmer 48 to start, stop oradjust neurostimulation therapy. In particular, patient programmer 48may permit patient to adjust stimulation parameters such as duration,amplitude, pulse width and pulse rate, within an adjustment rangespecified by the clinician via clinician programmer 46, or select from alibrary of stored stimulation therapy programs.

The implantable pulse generator 12, clinician programmer 46, and patientprogrammer 48 may communicate via cables or a wireless communication.Clinician programmer 46 and patient programmer 48 may, for example,communicate via wireless communication with the implantable pulsegenerator 12 using RF telemetry techniques known in the art. Clinicianprogrammer 46 and patient programmer 48 also may communicate with eachother using any of a variety of local wireless communication techniques,such as RF communication according to the 802.11 or Bluetoothspecification sets, infrared communication, e.g., according to the IrDAstandard, or other standard or proprietary telemetry protocols.

FIG. 3 also illustrates a general environment that may benefit from useof a tunneling tool in accordance with an embodiment of the presentdisclosure. Since the implantable pulse generator 12 is located remotelyfrom target location 50 for therapy, the therapy delivery element 14and/or the extension lead 16 is typically routed through a pathway 52subcutaneously formed along the torso of the patient to a subcutaneouspocket 54 where the implantable pulse generator 12 is located. As usedhereinafter, “lead” and “lead extension” are used interchangeably,unless content clearly dictates otherwise.

The therapy delivery elements 14 are typically fixed in place near thelocation selected by the clinician using the present suture anchors 60.The suture anchors 60 can be positioned on the therapy delivery element14 in a wide variety of locations and orientations to accommodateindividual anatomical differences and the preferences of the clinician.The suture anchors 60 may then be affixed to tissue using fasteners,such as for example, one or more sutures, staples, screws, or otherfixation devices. The tissue to which the suture anchors 60 are affixedmay include subcutaneous fascia layer, bone, or some other type oftissue. Securing the suture anchors 60 to tissue in this manner preventsor reduces the chance that the therapy delivery element 14 will becomedislodged or will migrate in an undesired manner.

FIG. 4 illustrates an epidural needle 70 configured to permit therapydelivery element 78 to be advanced into, and withdrawn from, an epiduralspace 72 (see FIG. 5) in accordance with an embodiment of the presentdisclosure. The epidural needle 70 includes an outer cannula 74 and aninner cannula 76. Removal of the inner cannula 76 creates and openingsized to receive a therapy delivery element 78. An epidural needlesuitable for implanting the therapy delivery element 78 is disclosed incommonly-assigned U.S. patent application Ser. No. 13/046,282, entitledEpidural Needle for Spinal Cord Stimulation, filed Mar. 11, 2011, whichis hereby incorporated by reference.

FIG. 5 is a schematic illustration of the epidural needle 70 located inthe epidural space 72 between the L1 and T12 vertebrae. The therapydelivery element 78 is inserted through the epidural needle 70 andpositioned in the epidural space 72 of the patient. Lead indicator 82 isattached to hub 84 of the epidural needle 70. The lead indicator 82 canalso be attached to the needle portion 70.

In one embodiment, the lead indicators 82 for the present leadidentification system are color coded. Any color scheme can be used. Oneapproach is the red-yellow-green color scheme used for traffic lightsthroughout the world, where the red light is always on the top and thegreen on the bottom. A similar color scheme can be used on the trialcable and the connector block on the IPG 12 so the colors also have afixed spatial relationship.

In another embodiment, the indicators 82 include both a color scheme andtactile indicators so the surgeon can identify the indicators bothvisually and by feel. For example, the lead indicators can havedifferent textures (e.g., smooth-textured-rough surface finish) or aunique shape (e.g., circle-square-triangle) that correspond to thered-yellow-green color scheme. In yet another embodiment, the indicatorsinclude alpha-numeric characters. While the present lead indicators arepreferably color coded, reference to a lead indicator should beunderstood to include a variety of indicators for use in the presentlead identification system.

FIGS. 6 and 7 illustrate an embodiment of a removable lead indicator 82suitable for attachment to the hub 84 of the epidural needles 70 inaccordance with an embodiment of the present disclosure. The removablelead indicator 82 includes slot 86 that permits it to engage with outercannula 74 illustrated in FIG. 4. In one embodiment, the lead indicator82 includes internal threads 88 that are configured to engage externalthreads 90 on the hubs 84. Alternatively, the lead indicator 82 can besnap-fit onto narrow portion 96 of the hubs 84.

In one embodiment, the lead indicators 82 are different colors (e.g.,red-yellow-green). In another embodiment, outer surface 83 includesdifferent sized recesses 85 corresponding to the red-yellow-green leadindicators 82. In yet another embodiment, alpha-numeric indicators 87can be added to the lead indicator 82. The different colors,alpha-numeric indicators, and recesses 85 can be used separately or incombination in accordance with the present lead identification system.

In another embodiment best illustrated in FIG. 4, an elastomeric sleeve97 is positioned in the narrow portion 96. The sleeve 97 includesindicia, such as for example different color strips. By rotating thesleeve 97 the surgeon can align the indicia marker 99 on the hub 84.Epidural needles 70 with rotating sleeves 97 can be configured toidentify any of the therapy delivery elements 78.

FIG. 8 illustrates an alternate removable lead indicator 92 suitable forattachment to the epidural needle 70 of FIG. 4. Flexible arms 94A, 94Belastically deform to permit engagement with the outer cannula 74 and/orthe hub 84. The lead indicators can include a variety of indicia, suchas color-coding. In the illustrated embodiment, the lead indicator 92also includes an identifying texture 98. For example, the leadindicators 92 can include smooth-textured-rough surfaces 98 used as partof the present lead identification system.

FIG. 9 illustrates a clip 102 adapted to attach proximal ends 100 of thetherapy delivery elements 78 to the patient in accordance with anembodiment of the present disclosure. The proximal ends 100 of thetherapy delivery elements 78 are preferably clipped or otherwiseattached to the patient or surgical drape during various phases of theimplantation process. In the illustrate embodiment, the clip 102includes three discrete receiving openings 104A, 104B, 104C (“104”)sized to receive proximal ends 100 of three therapy delivery elements78. Each receiving opening 104 includes a slot 106 to permit insertionof the therapy delivery element 78 and a lead indicator 108A, 108B, 108C(“108”), such as for example color-coded inserts. In one embodiment, theclip 102 is constructed from an elastomeric material. By bending theclip 102 in the direction 110, the size of the slots 106 increases tofacilitate engagement of the therapy delivery elements 78. The clip 102can be attached using clamps, adhesive tape, or a variety of othertechniques.

FIG. 10 illustrates one possible embodiment of the therapy deliveryelement 78 for use with the present lead identification system. Stylethandle 122 is attached to a stylet wire that extends through lumen 142(see FIG. 12) of the therapy delivery element 78. In the illustratedembodiment, the style handle 122 covers one or more of the contacts 124at proximal end 126 of the therapy delivery element 78. The stylethandle 122 is preferably detached from the therapy delivery element 78and moved in direction 128 a sufficient amount to expose all of thecontacts 124. Each contact 124 has a corresponding electrode 125 at thedistal end 127 of the therapy delivery element 78.

As illustrated in FIG. 11, the exposed contacts 124 on the proximal ends126 are then attached to connector blocks 130A, 130B, 130C, 130D, 130E(“130”) on trial cable connector 132. In the illustrated embodiment,trial cable connector 132 includes three eight contact connector blocks130A, 130B, 130C and two twelve contact connector blocks 130D, 130E.Trial stimulation of the therapy delivery elements 78 is then conductedas is known by those of skill in the art. The connector blocks 130include lead indicators 134, such as for example, color coding,alpha-numeric symbols, geometric shapes, and a variety of other leadindicators to identify the particular connector blocks 130.

Once the surgeon has confirmed that the therapy delivery elements 78 arelocated in the desired location within the epidural space 72, the stylethandle 122 and the attached stylet are removed. As illustrated in FIG.12, removable lead indicators 140 are inserted in the lumen 142 atproximal end 126 of each therapy delivery element 78. In the illustratedembodiment, the removable lead indicators 140 each include a stylet wire144 and a color indicator 146. The color indicators 146 preferably havea diameter less than or equal to the diameter of the therapy deliveryelement 78. In one embodiment, color indicators 146 are colored siliconetubing that compressively engages with the stylet wire 144. A clearshrink wrap is optionally applied over the silicone tubing.

The stylet wires 144 optionally include bends 148 to increase frictionwith the lumen 142. The bends 148 reduce the chance of the removablelead indicator 140 from inadvertently falling out of the lumens 142.

After a removable lead indicator 140 is inserted in each lumen 142, thetherapy delivery elements 78 are disconnected from the trial cableconnector 132. At this point, the proximal ends 126 of the therapydelivery elements 78 are free and the epidural needles 70 can be removedfrom the patient and slid off the proximal ends 126. The therapydelivery elements 78 will typically need to be temporarily disconnectedfrom the clip 102 to remove the epidural needles 70.

The present lead identification system provides corresponding leadindicators 82, 92, 102, 134, 140, and 150 that permit the surgeon totrack the electrodes 125 of a particular therapy delivery element 78 tothe correct connectors 124 on the implantable pulse generator 12. Sincethe lead indicators 82, 92, 102, 134, 140, and 150 are releasablyattachable to the components of the neurostimulation system, they can beshifted or reconfigured by the surgeon during the procedure. Forexample, two therapy delivery elements switch position during placement,or test stimulation shows the midline to be offset from its anticipatedlocation. The lead indicators are easily reconfigured during theprocedure to reflect the actual lead placement. As a result, thecomponents of the neurostimulation system, such as the epidural needles,the leads and lead extensions, lead clips, lead anchors, stylets,internal and external pulse generators, and trial cables can be genericwithout any labels or indicia. The use of removable lead indicatorsdramatically reduces the inventory of components for theneurostimulation system. As used herein, “corresponding lead indicator”refers to a lead indicator with indicia that can be correlated withindicia on at least one other lead indicator.

As illustrated in FIG. 13, each therapy delivery element 78 are attachedto the patient with an anchor 150 that preferably includes a leadindicator in accordance with an embodiment of the present disclosure. Inone embodiment, the anchors 150 are color coded to identify theindividual therapy delivery elements 78. Suitable anchors 150 aredisclosed in commonly-assigned U.S. patent application Ser. Nos.13/045,874, entitled Anchor for Implantable Medical Device, filed Mar.11, 2011; 13/045,947, entitled Anchor Sleeve for Implantable Sleeve,filed Mar. 11, 2011; and 13/046,182, entitled Pre-Sutured Anchor forImplantable Leads, filed Mar. 11, 2011, all of which are herebyincorporated by reference.

The surgeon then creates a pathway 152 between the incision site 154near the anchors 150 and the incision site 156 for the subcutaneouspocket 54 holding the implantable pulse generator 12 (see FIG. 3). Thepathway 152 is preferably created using a tunneling tool, such asdisclosed in commonly-assigned U.S. patent application Ser. No.13/046,144, entitled Tunneling Tool for Implantable Leads, filed Mar.11, 2011, which is hereby incorporated by reference.

After the tunneling step is completed, sheath 160 extends along thepathway 152. Proximal ends 126 of the therapy delivery elements 78 arepassed through lumen 162 in the sheath 160 to the incision site 156. Thesheath 160 is then removed from the patient by pulling it through theincision site 156 so that the therapy delivery elements 78 extendthrough the pathway 152 and out the incision site 156. The leadindicators 140 are then removed from the lumens 142 at the proximal ends126 of the therapy delivery elements 78. Each therapy delivery element78 is attached to a corresponding connector 22 on the implantable pulsegenerator 12. The connectors 22 are preferably color coded. Theimplantable pulse generator 12 is implanted in the subcutaneous pocket54 and the incision sites 154, 156 closed.

As will be discussed in detail below, the present method can be used forimplanting trial leads or permanent leads, using a variety ofprocedures. While the following flow charts use color coded leadindicators, it will be appreciated that a wide variety of otherindicators can be used with the methods of the present leadidentification system.

FIG. 14 is a flow chart summarizing a method for implanting a pluralityof trial leads using a lead identification system in accordance with anembodiment of the present disclosure. An epidural needle is insertedinto the patient for each trial lead (200). The stylets are removed fromthe epidural needles (202). The trial leads are inserted through eachepidural needle and positioned in the patient (204). A lead indicator isattached to each epidural needle (206). Proximal portions of the trialleads are preferably clipped to the patient using a clip with a leadindicator (208). The stylets are partially removed from each of thetrial leads to expose the contacts (210). The contacts at the proximalends of the trial leads are electrically coupled to color codedconnectors on a trial cable (212). Trial stimulation of the trial leadsis conducted to confirm lead placement (214). The stylets are removedfrom each of the trial leads (216) and color coded stylets are insertedin each of the trial lead lumens (218). The trial leads are thendisconnected from the trial cable (220). The epidural needles are slidoff the trial lead and are removed from the patient. The incision(s)around the trial leads are closed (222). The trial leads areelectrically coupled to connectors on the external pulse generator usedfor home trials and the exposed portions of the trial leads and theexternal pulse generator are attached to the patient for the home trial(224). After the home trial is completed, the trial leads are removedfrom the patient (226).

FIGS. 15A and 15B are flow charts summarizing a method for implanting aplurality of permanent leads using a lead identification system inaccordance with an embodiment of the present disclosure. An epiduralneedle is inserted into the patient for each permanent lead (250). Thestylets are removed from the epidural needles (252). The permanent leadsare inserted through each epidural needle and positioned in the patient(254). A different color indicator is attached to each epidural needle(256). The permanent leads are preferably clipped to the patient using acolor coded clip (258). The stylets are partially removed from each ofthe permanent leads to expose the contacts (260). The proximal ends ofthe permanent leads are electrically coupled to color coded connectorson a trial cable (262). Trial stimulation of the permanent leads isconducted to confirm lead placement (264). The permanent leads aredisconnected from the trial cable (266). The stylets are removed fromeach of the permanent leads (268) and color coded stylets are insertedin each of the permanent lead lumens (270).

The epidural needles are slid off the permanent leads and removed fromthe patient (272). The permanent leads are attached to the patient usingcolor coded anchors (274). A passageway is tunneled to the IPG site(276). Proximal ends of the permanent leads are passed through a lumenin the tunneling sheath (278). The color coded stylets are removed fromthe proximal ends of the permanent leads (280). The proximal ends of thepermanent leads are then electrically coupled to corresponding colorcoded connectors on the IPG (282). The IPG is implanted and the incisionsites are closed (284).

FIGS. 16A and 16B are flow charts summarizing a method for implanting aplurality of permanent leads with trial lead extensions using a leadidentification system in accordance with an embodiment of the presentdisclosure. An epidural needle is inserted into the patient for eachpermanent lead (300). The stylets are removed from the epidural needles(302). The permanent leads are inserted through each epidural needle andpositioned in the patient (304). A different color indicator is attachedto each epidural needle (306). The permanent leads are preferablyclipped to the patient using a color coded clip (308). The stylets arepartially removed from each of the permanent leads to expose thecontacts (310). The proximal ends of the permanent leads areelectrically coupled to color coded connectors on a trial cable (312).Trial stimulation of the permanent leads is conducted to confirm leadplacement (314). The stylets are removed from each of the permanentleads (316) and color coded stylets are inserted in each of thepermanent lead lumens (318). The permanent leads are disconnected fromthe trial cable (320). The epidural needles are removed from the patientand slid off the permanent leads (322). The permanent leads are attachedto the patient using color coded anchors (324). The color coded styletsare transferred from the permanent leads to proximal ends of trial leadextensions (326).

Distal ends of the trial lead extensions are connected to color codedproximal ends of the permanent leads (328). A passageway is tunneled tothe IPG site (330). Proximal ends of the trial lead extensions arepassed through a lumen in the tunneling sheath (332). The color codedstylets are removed from the proximal ends of the trial lead extensions(334). The proximal ends of the trial lead extensions are thenelectrically coupled to corresponding color coded connectors on thetrial cable (336). The incision sites are closed (338). The trial pulsegenerator and trial cable are attached to the patient for home trial(340).

FIG. 16C is a flow chart summarizing a method for implanting a pluralityof permanent leads, with or without permanent lead extensions, using alead identification system in accordance with an embodiment of thepresent disclosure. The incision site where the trial lead extensionsare connected to the permanent leads is opened (350). The trial leadextensions are disconnected from the permanent leads (352). Color codedstylets are inserted into proximal ends of the permanent leads (354).The connectors on the trial lead extensions are cut-off and removed fromthe patient (356). The proximal ends of the trial lead extensions arepulled to remove from the patient (358). A passageway is tunneled to theIPG site (360). If the permanent leads are not long enough to reach theIPG site, permanent lead extensions are attached to the permanent leads(262). Color coded stylets are inserted in the proximal ends of thepermanent leads (or the proximal ends of the permanent lead extensions)(264). The proximal ends of the permanent leads (or the permanent leadextensions) are passed through the tunneling sheath, and the tunnelingsheath is removed (366). The color coded stylets are removed from theproximal ends of the permanent leads (or the permanent lead extensions)(368). The proximal ends of the permanent leads (or the permanent leadextensions) are electrically coupled to corresponding color codedconnectors on the IPG (370). The IPG is implanted and the incisions areclosed (372).

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range is encompassed within this disclosure. The upper and lowerlimits of these smaller ranges which may independently be included inthe smaller ranges is also encompassed within the disclosure, subject toany specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either bothof those included limits are also included in the disclosure.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosure belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the various methods and materials arenow described. All patents and publications mentioned herein, includingthose cited in the Background of the application, are herebyincorporated by reference to disclose and described the methods and/ormaterials in connection with which the publications are cited.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present disclosure isnot entitled to antedate such publication by virtue of prior invention.Further, the dates of publication provided may be different from theactual publication dates which may need to be independently confirmed.

Other embodiments are possible. Although the description above containsmuch specificity, these should not be construed as limiting the scope ofthe disclosure, but as merely providing illustrations of some of thepresently preferred embodiments. It is also contemplated that variouscombinations or sub-combinations of the specific features and aspects ofthe embodiments may be made and still fall within the scope of thisdisclosure. It should be understood that various features and aspects ofthe disclosed embodiments can be combined with or substituted for oneanother in order to form varying modes disclosed. Thus, it is intendedthat the scope of at least some of the present disclosure should not belimited by the particular disclosed embodiments described above.

Thus the scope of this disclosure should be determined by the appendedclaims and their legal equivalents. Therefore, it will be appreciatedthat the scope of the present disclosure fully encompasses otherembodiments which may become obvious to those skilled in the art, andthat the scope of the present disclosure is accordingly to be limited bynothing other than the appended claims, in which reference to an elementin the singular is not intended to mean “one and only one” unlessexplicitly so stated, but rather “one or more.” All structural,chemical, and functional equivalents to the elements of theabove-described preferred embodiment that are known to those of ordinaryskill in the art are expressly incorporated herein by reference and areintended to be encompassed by the present claims. Moreover, it is notnecessary for a device or method to address each and every problemsought to be solved by the present disclosure, for it to be encompassedby the present claims. Furthermore, no element, component, or methodstep in the present disclosure is intended to be dedicated to the publicregardless of whether the element, component, or method step isexplicitly recited in the claims.

1. A method of implanting a plurality of trial neurostimulation leads ina patient, the method comprising the steps of: inserting an epiduralneedle into the patient for each trial lead; inserting a trial leadthrough each epidural needle and positioning the trial lead in thepatient; attaching a removable lead indicator to each epidural needle;electrically coupling proximal ends of the trial leads to connectorshaving corresponding lead indicators on a trial cable; conducting trialstimulation of the trial leads to confirm lead placement; insertingcorresponding lead indicator stylets in lumens of each of trial lead;disconnecting the trial leads from the trial cable; removing theepidural needles from the patient by sliding the epidural needles off ofthe trial leads and over the lead indicator stylets; closing incisionsaround the trial leads; electrically coupling the trial leads toconnectors on an external pulse generator having corresponding leadindicators, where the lead indicators permit a surgeon to track eachtrial lead to a corresponding connector on the external pulse generator;and conducting a trial of the neurostimulation leads.
 2. The method ofclaim 1 wherein the lead indicators comprises one or more of colorindicators, tactile indicators, alpha-numeric indicators, or acombination thereof.
 3. The method of claim 1 comprising the step ofrepositioning at least two of the lead indicators while implanting thetrial neurostimulation leads.
 4. The method of claim 1 comprising thestep of switching the removable lead indicators on at least two of theepidural needles while implanting the trial neurostimulation leads. 5.The method of claim 1 comprising the step of switching the leadindicator stylets on at least two of the trial leads while implantingthe trial neurostimulation leads.
 6. The method of claim 1 comprisingthe step of attaching proximal portions of the trial leads to a clipwith corresponding lead indicators.
 7. The method of claim 1 comprisingthe step of removing the trial leads from the patient after the trialperiod is completed.
 8. A method of implanting a plurality of permanentneurostimulation leads in a patient, the method comprising the steps of:inserting an epidural needle into the patient for each permanent lead;inserting a permanent lead through each epidural needle and positioningthe permanent lead in the patient; attaching a removable lead indicatorto each epidural needle; electrically coupling proximal ends of thepermanent leads to connectors on a trial cable having corresponding leadindicators; conducting trial stimulation of the permanent leads toconfirm lead placement; inserting corresponding lead indicator styletsin lumens of each of permanent lead; disconnecting the permanent leadsfrom the trial cable; removing the epidural needles from the patient bysliding the epidural needles off of the permanent leads and over thelead indicator stylets; passing proximal ends of the permanent leadswith the corresponding lead indicator stylets through one or more lumensto an implantable pulse generator located at a remote implantation sitein the patient; removing the corresponding lead indicator stylets fromthe lumens of the permanent leads; electrically coupling the proximalends of the permanent leads to connectors on an implantable pulsegenerator having corresponding lead indicators, where the leadindicators permit a surgeon to track each permanent lead to acorresponding connector on the implantable pulse generator; and closingincision sites around the permanent leads and the implantable pulsegenerator.
 9. The method of claim 8 wherein the lead indicatorscomprises one or more of color indicators, tactile indicators,alpha-numeric indicators, or a combination thereof.
 10. The method ofclaim 8 comprising the step of repositioning at least two of theremovable lead indicators while implanting the trial neurostimulationleads.
 11. The method of claim 8 comprising the step of switching theremovable lead indicators on at least two of the epidural needles whileimplanting the permanent neurostimulation leads.
 12. The method of claim8 comprising the step of switching the lead indicator stylets on atleast two of the permanent leads while implanting the permanentneurostimulation leads.
 13. The method of claim 8 comprising the stepsof attaching proximal portions of the permanent leads to a clip withcorresponding lead indicators.
 14. The method of claim 8 comprisingattaching the permanent leads to the patient using anchors havingcorresponding lead indicators.
 15. A method of implanting a plurality ofpermanent neurostimulation leads with trial lead extensions in apatient, the method comprising the steps of: inserting an epiduralneedle into the patient for each permanent lead; inserting a permanentlead through each epidural needle and positioning the permanent lead inthe patient; attaching a removable lead indicator to each epiduralneedle; electrically coupling proximal ends of the permanent leads toconnectors on a trial cable having corresponding lead indicators;conducting trial stimulation of the permanent leads to confirm leadplacement; inserting corresponding lead indicator stylets in lumens ofeach of permanent lead; disconnecting the permanent leads from the trialcable; removing the epidural needles from the patient by sliding theepidural needles off of the permanent leads and over the lead indicatorstylets; transferring the lead indicator stylets from the permanentleads to lumens at proximal ends of the trial lead extensions;connecting distal ends of the trial lead extensions to proximal ends ofthe corresponding permanent leads; passing proximal ends of the triallead extensions with the corresponding lead indicator stylets throughone or more lumens to a remote implantation site in the patient;removing the corresponding lead indicator stylets from the lumens of thetrial lead extensions; electrically coupling the trial leads toconnectors on an external pulse generator having corresponding leadindicators, where the lead indicators permit a surgeon to track eachpermanent lead to a corresponding connector on the external pulsegenerator; and conducting a trial of the neurostimulation leads.
 16. Themethod of claim 15 comprising the step of attaching proximal portions ofthe permanent leads to a clip with corresponding lead indicators. 17.The method of claim 15 comprising the step of attaching the permanentleads to the patient using anchors having corresponding lead indicators.18. A method of connecting a plurality of permanent neurostimulationleads each having a trial lead extension implanted a patient to animplantable pulse generator, the method comprising the steps of: openingan incision site where the trial lead extensions are connected to thepermanent leads; disconnecting the permanent leads from the trial leadextensions; inserting a lead indicator stylet in lumens at proximal endsof the permanent leads; removing the trial lead extensions from thepatient; passing proximal ends of the permanent leads with thecorresponding lead indicator stylets through one or more lumens to aremote implantation site in the patient; removing the corresponding leadindicator stylets from the lumens of the permanent leads; electricallycoupling the permanent leads to connectors on an implantable pulsegenerator having corresponding lead indicators, where the leadindicators permit a surgeon to track each permanent lead to acorresponding connector on the implantable pulse generator; and sealingthe implantable pulse generator in the implantation site in the patient.19. A method of connecting a plurality of permanent neurostimulationleads each having a trial lead extension implanted a patient to animplantable pulse generator, the method comprising the steps of: openingan incision site where the trial lead extensions are connected to thepermanent leads; disconnecting the permanent leads from the trial leadextensions; inserting a lead indicator stylet in lumens at proximal endsof the permanent leads; removing the trial lead extensions from thepatient; transferring the lead indicator stylet to lumens at proximalends of a plurality of permanent lead extensions; attaching distal endsof the permanent lead extensions to the permanent leads; passing theproximal ends of the permanent lead extensions with the correspondinglead indicator stylets through one or more lumens to a remoteimplantation site in the patient; removing the corresponding leadindicator stylets from the lumens of the permanent lead extensions;electrically coupling the permanent lead extensions to connectors on animplantable pulse generator having corresponding lead indicators, wherethe lead indicators permit a surgeon to track each permanent lead to acorresponding connector on the implantable pulse generator; and sealingthe implantable pulse generator in the implantation site in the patient.20. A neurostimulation system comprising: a plurality of therapydelivery elements each comprising a proximal end with a plurality ofelectrical contacts adapted to electrically couple with an implantablepulse generator and a distal end with a plurality of electrodeselectrically coupled to the electrical contacts; a plurality ofremovable lead indicators each adapted to attach to one of a pluralityof epidural needles to uniquely identify each of the therapy deliveryelements; at least one clip with corresponding lead indicators adaptedto releasably attach to proximal ends of the therapy delivery elements;a trial cable having connectors with corresponding lead indicatorsadapted to conduct trial stimulation of the therapy delivery elements; aplurality of removable lead indicator stylets adapted to be insertedinto lumens at proximal ends of each of the therapy delivery elements;and a pulse generator with connectors having corresponding leadindicators, where the lead indicators permit a surgeon to trackelectrodes on a particular therapy delivery element to a correspondingconnector on the implantable pulse generator.
 21. The leadidentification system of claim 20 wherein the lead indicators comprisesone or more of color indicators, tactile indicators, alpha-numericindicators, or a combination thereof.
 22. The lead identification systemof claim 20 wherein the therapy delivery elements comprise one of trialleads or permanent leads.
 23. The lead identification system of claim 20wherein the pulse generator comprises one of an external pulse generatorfor conducting trials or an implantable pulse generator.
 24. The leadidentification system of claim 20 comprising one or more lead anchorswith corresponding lead indicators adapted to attach the therapydelivery elements to the patient.
 25. The lead identification system ofclaim 20 wherein the lead indicator stylets comprise a diameter lessthan, or equal to, a diameter of the therapy delivery elements.
 26. Thelead identification system of claim 20 comprising rotating leadindicators attach to each of the epidural needles wherein a rotationalorientation of the rotating lead indicators uniquely identify each ofthe therapy delivery elements.
 27. A lead identification system fortracking a plurality of therapy delivery elements during implantation ina patient using a plurality of epidural needles to correspondingconnectors on an implantable pulse generator, the lead identificationsystem comprising: a plurality of removable lead indicators each adaptedto attach to one of the plurality of epidural needles to uniquelyidentify each of the therapy delivery elements; at least one clip withcorresponding lead indicators adapted to releasably attach to proximalends of the therapy delivery elements; and a plurality of removable leadindicator stylets adapted to be inserted into lumens at proximal ends ofeach of the therapy delivery elements.
 28. The lead identificationsystem of claim 27 comprising at least one clip with corresponding leadindicators adapted to releasably attach to proximal ends of the therapydelivery elements.
 29. The lead identification system of claim 27comprising a trial cable having connectors with corresponding leadindicators adapted to conduct trial stimulation of the therapy deliveryelements.
 30. The lead identification system of claim 27 comprising apulse generator with connectors having corresponding lead indicators.31. The lead identification system of claim 27 wherein the leadindicator stylets comprise a diameter less than, or equal to, a diameterof the therapy delivery elements.
 32. The lead identification system ofclaim 27 comprising rotating lead indicators attach to each of theepidural needles wherein a rotational orientation of the rotating leadindicators uniquely identify each of the therapy delivery elements.